The aim of this study was to assess the usefulness of brain magnetic resonance imaging (MRI) using Diffusion-weighted imaging (DWI) and T2*-weighted imaging (T2*WI) to differentiate between cerebral embolism caused by infectious endocarditis (IE) and cancer-related stroke.

The incidence of IE in cancer patients is rising. Cerebral embolism in multiple vascular territories can occur both in IE and hypercoagulability associated with cancer. Since the treatment for these two conditions is different, it is important to distinguish between these two etiologies. Anticoagulation is contraindicated in IE; however, anticoagulation with low-molecular-weight heparin is recommended in cancer-related stroke.

A retrospective analysis was performed for 52 patients with IE and 38 patients with cancer-related stroke who were admitted to our hospital from January 2012 to August 2022. IE was diagnosed using modified Duke criteria, and patients with cancer-related stroke had a previously confirmed diagnosis of cancer. DWI and T2*WI were analyzed.

Among 52 patients with IE, 10 demonstrated no abnormalities on the brain MRI. The number of patients with cerebral embolism in two or more vascular territories as detected using DWI were 39 cases (75%) for IE and 34 cases (89.5%) for cancer-related stroke, respectively. Three cases (5.8%) of clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) were found only in the IE group. Among patients with cerebral embolism in multiple vascular territories as detected on DWI, 29 patients (74.4%) with IE and 5 (14.7%) with cancer-related stroke demonstrated low T2* signal, with a sensitivity of 74.3% and specificity of 85.2%, respectively.

Multi-territorial acute ischemic stroke accompanied with T2*-weighted hypointense signal spots is highly suggestive of cerebral embolism attributable to IE.